Regions
Northwest Inland.
Confidence
Fair - Due to limited field observations
Weather Forecast
Synopsis: A weak frontal system is forecast to move through on Friday night and into Saturday. Conditions should begin to dry out and clear on Sunday and Monday as a ridge of high pressure forms.Saturday: Cloudy with light snow – 5-10 cm. The freezing level is around 1000 m. Winds are moderate from the south-southeast. Sunday: Sunny breaks. The freezing level rises to 1400m during the day and winds are light from the north. Monday: A mix of sun and cloud. The freezing level is steady around 1400-1500 m.
Avalanche Summary
Solar induced avalanche activity tapered off over the past couple days as temperatures cooled slightly. Previous activity included loose wet sluffs up to size 2 on steep sun-exposed slopes. Cornices and glide cracks continue to fail with some regularity.
Snowpack Summary
5-10 cm of new snow sits on a variety of old snow surfaces including a melt-freeze crust, moist snow, sugary facets, and wind affected snow. Pockets of wind slab could develop in exposed lee terrain over the next several days. 30 - 60 cm of snow overlies a crust, old wind slabs or surface hoar layer buried on March 9th. The distribution of the surface hoar is also highly variable and it does not exist in every drainage. I would still remain cautious and continue to dig and test before diving into my line. Deeper in the snowpack, basal facets may resurface as a concern with continued mild temperatures.Cornices have become well-developed and could easily become unstable during periods of warm weather or direct solar radiation.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.